McDonnell Douglas Phase B 12-Man Space Station (1970)

Image: MDAC/NASA.

In the autumn of 1966, NASA asked President Lyndon Baines Johnson’s Bureau of the Budget (BOB) for $100 million in Fiscal Year (FY) 1968 to begin Phase B contractor studies of Earth-orbital space stations. With the Apollo Program’s culmination drawing near, the U.S. civilian space agency was eager to establish post-Apollo goals, and topping its wish-list was a space station – an Earth-orbiting laboratory for testing the effects on men and machines of long-term exposure to space conditions and for performing scientific and technological experiments and Earth and space observations.

NASA had performed internal Phase A space station studies almost since it opened its doors in October 1958. If NASA had had its way, a space station would have preceded Apollo’s reach for the moon. President John F. Kennedy’s May 1961 call for a man on the moon ahead of the Russians and before the end of the 1960s had, however, preempted space station development. The FY 1968 funding request was in some sense a plea to restore NASA’s program to the traditional space station/moon/Mars progression spaceflight thinkers had promoted since the 1920s.

The BOB turned down NASA’s request; then, in January 1967, the Apollo 1 fire profoundly altered the space policy environment. NASA came under increased scrutiny and funding for post-Apollo space goals became even more restricted. Congress dealt the only approved post-Apollo manned program – the Apollo Applications Program (AAP), which would reapply Apollo lunar mission hardware to new goals, including a series of Earth-orbiting laboratories based on spent S-IVB rocket stages – a nearly half-billion-dollar funding cut in August 1967.

NASA recovered from the fire – in November 1967, the successful first flight test of the three-stage Saturn V moon rocket did much to restore confidence – but funding for post-Apollo programs was still not forthcoming. When NASA Administrator James Webb, who had led the agency from Apollo’s beginning, announced in September 1968 that he would step down, he told journalists that NASA was “well prepared. . .to carry out the missions that have been approved.” He added, however, that “[w]hat we have not been able to do under the pressures on the budget has been to fund new missions. . .”

5 March 1969: President Richard Nixon (left) announces that he has appointed Thomas Paine (center) to serve as NASA Administrator as Vice President Spiro Agnew looks on. The Senate would confirm Paine on 20 March. Image: NASA.

Webb’s deputy, Thomas Paine, became Acting NASA Administrator. Webb, whose earliest Federal government experience dated to 1932, had deftly piloted NASA through Washington’s political shoals; Paine, by contrast, had just seven months of experience in government service. Paine displayed his inexperience almost immediately by pressing President Johnson for a space station decision in the final weeks of his Administration. Johnson deferred the decision to the next President.

Soon after President Richard M. Nixon’s January 1969 inauguration, Democrat Paine submitted his resignation as was customary; Republican Nixon, however, surprised everyone by keeping him on and appointing him as Webb’s formal replacement. Paine then made another Space Station pitch. He apparently hoped that Apollo Program successes would induce the new President to give NASA a blank check for future projects.

Though the Apollo 8 Command and Service Module (CSM) had triumphantly orbited the moon and returned its three-man crew safely to Earth less than a month before his inauguration, Nixon refused to commit to new NASA programs. Instead, he postponed any decision on NASA’s future direction at least until after the newly appointed Space Task Group (STG) completed its report in September 1969. Paine was a voting member of the STG, which was chaired by Vice-President Spiro Agnew.

It is widely assumed today that Nixon kept Paine on in case Apollo failed. In the event that the first moon landing ended in grief, he wanted a hold-over from the Democratic Johnson Administration upon whom he could hang the blame. At the time, however, even as savvy an aerospace trade publication as Aviation Week & Space Technology assumed that Nixon was impressed with Paine’s abilities. Nixon, it must be said, was less impressed with the talents of the people with whom he surrounded himself than he was with their obedience.

Paine chose not to await the outcome of the STG’s deliberations. In January-February 1969, he oversaw creation within NASA of a Space Station Task Force, a Space Station Steering Group, and an independent Space Station Review Group. These bodies prepared a Phase B Space Station Study Statement of Work (SOW), which NASA released to industry on 19 April 1969.

The SOW solicited proposals to study a 12-man Space Station, the design of which would eventually serve as a building block for a 100-man Earth-orbital Space Base. The 12-man Space Station was to reach orbit on a Saturn V rocket in 1975 and to remain in operation for 10 years. Of the contract0r effort expended in the Phase B study, 60% was to be devoted to the 12-man Space Station, 15% to its future role as part of the 100-man Space Base, 15% to an interim logistics spacecraft for delivering early crews and supplies to the 12-man Space Station, and 10% to 12-man Space Station interfaces with an advanced logistics system (specifically, a winged, fully reusable Space Shuttle).

Grumman, North American Rockwell (NAR), and McDonnell Douglas Astronautics Company (MDAC) submitted proposals. On 22 July 1969 – two days after the successful Apollo 11 moon landing – NASA awarded to NAR and MDAC Phase B Space Station study contracts worth $2.9 million each. This was a far cry from the $100 million Webb had sought in late 1966 to fund Phase B studies.

Phase B study work began formally in September 1969, though the contractors had begun to put together industry teams and spend their own money on the study even before NASA issued its SOW. The MDAC and NAR Phase B study teams each included more than 30 subcontractors. NAR and MDAC were eager to move forward at their own expense because they expected that the eventual Phase C/D Space Station development contract would be extremely lucrative.

In March 1969, the U.S. Department of State had come out cautiously in favor of NASA’s proposed Space Station/Space Shuttle program because it expected that it might open up opportunities for international cooperation. With that in mind, NASA invited foreign representatives to participate in the Phase B study’s quarterly reviews. In early June 1970, as the Phase B study neared its planned conclusion, the European Space Research Organization (ESRO) returned the favor by inviting NAR and MDAC to present briefings on their Phase B studies in Paris.

AAP, meanwhile, was renamed the Skylab Program in February 1970. The new name reflected AAP’s abandonment of all missions not related to the Orbital Workshop. The first of two planned Skylab Orbital Workshops was designated Skylab A.

C. J. Dorrenbacher, MDAC’s Vice President for Advance Systems and Technology, began his presentation by drawing links between his company’s 12-man Space Station design and Skylab A, which he said was scheduled to launch during 1972. The Skylab Program, he told the Paris meeting, would see NASA manned spaceflight evolve from “cockpit to space ship accommodations.” He explained that Skylab would contain “many systems that are prototypes of those to be used on the Space Station,” and added that “experience in the operation, maintenance, and habitability of [Skylab] will significantly extend our knowledge and, thus, our confidence in the Space Station Program.”

Like Skylab, MDAC’s Space Station would leave Earth on a two-stage Saturn V. Designated INT-21, the rocket would comprise S-IC and S-II stages measuring 9.2 meters in diameter. This established the maximum diameter of MDAC’s Space Station. The S-II second stage would inject the bullet-shaped 34-meter-long Station into a 456-kilometer-high circular orbit inclined 55° relative to Earth’s equator. Its labors completed, the S-II stage would then detach and deorbit itself over a remote ocean area.

MDAC’s Station would comprise two main modules: the two-deck, roughly conical artificial-gravity module at its front end and the four-deck, drum-shaped core module. The 15-meter-long core module would be divided into two independent sections, each with a research deck and a living deck. The artificial-gravity module would make up a third living deck/research deck combination. Each of the three sections would have independent life-support systems and could house the entire Station crew in an emergency. The artificial-gravity and core modules would also each include an unpressurized equipment compartment.

Soon after reaching orbit, MDAC’s Station would discard a streamlined nosecone covering its front docking port. A “telescoping spoke” linking the artifical-gravity and core modules would then extend to separate the two modules by a few meters. This would expose the core module’s equipment compartment, enabling four large radio dish antennas to deploy and exposing waste heat radiators for the Station’s twin Isotope/Brayton (I/B) nuclear power units. The I/B units, which would each produce 10 kilowatts of electricity, would be designed to jettison from the Station in an emergency and safely reenter Earth’s atmosphere.

By the time of the Paris briefings, NASA had pushed back the planned launch of the 12-man Space Station to 1977. Though this move was inspired by increasingly disheartening NASA budget projections, space agency officials hoped that the two-year slip would also help to ensure that the Shuttle would be ready to deliver astronauts, supplies, equipment, and experiment modules to the orbiting Station, eliminating any need for an interim logistics vehicle. For its study, MDAC assumed a Shuttle consisting of a piloted winged Booster and a piloted winged Orbiter with a 4.6-by-18.3-meter cargo bay.

Flight controllers on Earth would remotely check out the Station’s vital systems. If it checked out as habitable, then 24 hours after it reached orbit its first 12 residents would lift off from Cape Kennedy om board a Shuttle. Eight hours later, their Orbiter would rendezvous with the Station and open its cargo bay doors. The crew would depart the cargo bay inside an 18,000-kilogram Crew/Cargo Module (CCM). MDAC’s CCM, an Apollo-CSM-sized independent spacecraft, resembled designs for drum-shaped cargo spacecraft and small space station modules based on Gemini spacecraft hardware put forward by McDonnell Aircraft as early as 1962. Gemini, which carried 10 two-man crews into Earth orbit in 1965-1966, was manufactured by McDonnell before its April 1967 merger with Douglas Aircraft created MDAC. The company probably viewed the CCM as a way of salvaging its interim logistics vehicle design in a Shuttle-based logistics resupply system.

The CCM would deploy four side-mounted engine modules and maneuver to a docking at the Station’s aft port on the core module. The astronauts would then enter the Station and begin checking out its systems. If initial Station manning came off without a hitch, the Orbiter, which would remain close by the Station but would not dock, would commence its return to Earth twenty-five hours after the CCM bearing the Station crew left its cargo bay.

A Shuttle would subsequently deliver a CCM to MDAC’s Station every 90 days with fresh astronauts and supplies. Of the CCM’s mass, about 13,000 kilograms would comprise cargo. After a new CCM docked carrying a new crew, the crew already on board the Station would board their CCM, undock, maneuver to the waiting Orbiter, and enter its cargo bay. The Orbiter would then close its cargo bay doors and return to Earth.

The 1.5-meter hatch through which the first astronauts would enter their new home would open into the core module’s central “tunnel.” Besides forming the main “artery” linking the core module’s four pressurized decks, the three-meter-diameter cylinder would provide emergency living quarters for the entire crew, a 180-day supply of emergency food, a passageway for ducts and conduits, radiation-shielded photographic film storage, and space suit storage. MDAC thus rejected the concept of a separate Space Station life boat that could evacuate the crew in the event of trouble while a Shuttle Orbiter was not present in favor of a “fall-back” shelter where the crew could await rescue.

At the forward end of the four-level core module tunnel, a 1.5-meter hatch would open into a cylindrical airlock. The airlock would occupy the center of the core module’s unpressurized equipment compartment. A hatch in the airlock wall would open into the equipment compartment, which would contain liquid and gas tanks, the twin I/B units, their waste heat radiators and power conditioning and distribution subsystems, and unpressurized storage. A 1.5-meter hatch in the airlock ceiling would open into the telescoping spoke leading to the artificial-gravity module.

The telescoping spoke would link to a central tunnel connecting the artificial-gravity module’s two decks. A 1.5-meter hatch at the forward end of the tunnel would open into a cylindrical airlock at the center of the artificial-gravity module’s unpressurized equipment module. A hatch in the airlock’s side would provide access to unpressurized storage, gas and liquid tanks, and small thrusters and propellant tanks. The equipment compartment would also include a place for the eventual installation of a third I/B power unit. A hatch in the airlock ceiling would connect to the Station’s front docking port.

Dorrenbacher told his European audience that the Station’s first crew would almost immediately begin a 30-day artificial-gravity experiment. This would entail extending the telescoping spoke to its maximum length. Six crew members would take up residence in the artificial-gravity module, while “some” would occupy a small “zero-gravity cab” inside the spoke at the Station’s center of mass.

The astronauts would then ignite the small thrusters in the artificial-gravity module’s equipment compartment to set the Station spinning at a rate of four rotations per minute about its center of mass. This would produce acceleration which the crew would feel as gravity. On Deck 1 of the core module, 19.2 meters from the center of mass, the astronauts would feel acceleration equivalent to 0.35 Earth gravities. On the artificial-gravity module’s living deck (Deck 6), 39.3 meters from the center of mass, the astronauts would feel 0.7 Earth gravities.

After a month of artificial-gravity experimentation, the astronauts would halt the Station’s rotation using the small thrusters, restoring it to a zero-gravity condition. The artificial-gravity module thrusters would carry enough propellants to permit up to four similar experiments.

Dorrenbacher described the 12-man Space Station as “a research facility to accommodate all experiment disciplines. . .a general-purpose laboratory.” Of its three experiment decks, Deck 2 would at launch from Earth be dedicated to the study of living things in zero gravity. It would include the Station’s medical dispensary and isolation ward. Deck 4 would constitute a general purpose laboratory that would serve both scientific support and engineering roles. It would include a drum-shaped experiment & test isolation facility, a mechanical lab, an electronics/electrical lab, a hard-data processing facility, an optics facility, and a small experiment airlock. Deck 5 would include a centrifuge with a pair of cabs large enough to accommodate men and experiments.

Based on NASA input, MDAC defined eight experiment disciplines for its Station. These were astronomy, space physics, space biology, Earth survey, aerospace medicine, space manufacturing, engineering/operations, and advanced technology. Not all disciplines could be accommodated simultaneously; for example, the artificial-gravity experiment series would preclude experiments which needed a stable platform and zero gravity.

Image: MDAC/NASA.Image: MDAC/NASA.

Dorrenbacher then provided a rough schedule of the Station’s experiment programs. Biomedical experimentation would begin with the arrival of the first crew and continue without pause throughout the Station’s planned 10-year operational lifetime, as would “man-system integration” experiments. In general, early research not associated with the artificial-gravity experiment series would focus on Station operations and habitability. “Component test” experiments would end in early 1978, “maintenance and logistic” experiments would conclude in late 1978, and “occupancy and space living,” “contamination,” and “exposure” research would end in mid-1979.

CCMs would deliver new experiment apparatus to replace and augment that launched with the Station, Dorrenbacher told the Paris meeting. Disused experiment hardware and other equipment and furnishings would be packed into CCMs for return to Earth. He suggested that, following the conclusion of the artificial-gravity experiment series in late 1978, furnishings on Deck 6 should be returned to Earth so that it could be converted into a physics & chemistry laboratory using new apparatus delivered by CCMs.

By then, the first Attached Modules (AMs) and Free-Flying Modules (FFMs) would arrive at MDAC’s Station in a Shuttle Orbiter cargo bay. One AM, devoted to Ultraviolet (UV) Stellar Astronomy, would dock with a port on the core module’s side linking it to the deck 4 general-purpose lab. Another AM, devoted to Earth Surveys, would dock either at Deck 4’s second port or at a port on Deck 2. Two FFMs, devoted respectively to Solar Astronomy and High-Energy Stellar Astronomy, would dock with the Station’s front port when they needed servicing; for example, after they had expended their supplies of photographic film. AMs would rely on the Station for electrical power, while FFMs would each sport a pair of electricity-generating solar array wings.

Fully operational MDAC Space Station with Y and Z directions and decks marked. “Logistics” modules correspond to CCMs. A Free-Flyer Module docked at the front port is shown without solar arrays. Image: MDAC/NASA.

CCMs, meanwhile, would deliver experiment subjects: besides a steady supply of new astronauts, beginning in early 1979 they would transport to the Station small vertebrates such as rats and invertebrates such as fruit flies. Vascular plants would first reach the Station late that same year.

Also in late 1979, the general Stellar Astronomy FFM would arrive near the Station. MDAC envisioned that UV Stellar Astronomy and High-Energy Stellar Astronomy would conclude at the beginning of 1981, while Solar Astronomy, general Stellar Astronomy, small vertebrate, invertebrate, and plant studies would continue until the Station reached its planned end-of-life in 1987. Biomedical centrifuge and fluid physics AMs would arrive in late 1981, with the former remaining with the Station until end-of-life and the latter departing in late 1985. Small Vertebrates Centrifuge and Infrared Stellar Survey AMs would arrive in late 1982 and remain docked until Station end-of-life.

Late 1983 would see arrival of the Remote Maneuvering Satellite (RMS), which would take up residence in a “hangar” in the airlock linked to the Station’s front port in the artificial-gravity module. Dorrenbacher called the RMS a “subsatellite,” but did not otherwise describe its role. At about the same time, the X-Ray Telescope FFM and advanced particle & plasma physics experiment apparatus would arrive. The X-Ray Telescope FFM would operate through Station end-of-life. Some advanced physics experiments would cease in early 1985, and RMS operations and the remaining advanced physics experiments would cease in late 1986. Late 1985 would see the arrival of materials science experiment apparatus and the Cosmic-Ray Physics FFM, both of which would remain in operation through Station end-of-life.

Dorrenbacher described how the vast quantity of data generated by Station experiments could reach Earth. MDAC estimated that 9070 kilograms of magnetic tape, microfilm, exposed photographic and X-ray film, and photographic plates would need to be returned to Earth each year. The Station’s four large dish antennas would enable continuous two-way television communication direct through ground stations or through relay satellites so that Station and Earth researchers could work together continuously in real time. The antennas would be capable of transmitting up to a trillion bits (one terabyte) of data to Earth each day.

The Station’s impressive experiment capability would demand careful management of crew time. MDAC assumed that the astronauts would work around the clock, with six men on duty and six men off duty at any one time. Each 12-man crew would include eight scientist/engineers and four Station flight-crew. Four scientist/engineers and two flight-crew would work during each 12-hour shift. One scientist/engineer would serve as principal scientist; he would work with the flight-crew commander, who would have responsibility for the safety of the entire crew, to ensure that science interests were taken into account during Station operations. Two scientist/engineers would serve as principal investigator representatives; they would work directly with scientists on Earth.

Image: MDAC/NASA.Image: MDAC/NASA.

Off-duty crewmembers would spend most of their time on the living decks (Decks 1, 3, and – during the artificial-gravity experiment – 6). There, Dorrenbacher explained, they would have at their disposal private staterooms with 4.6 meters of floor space for “relaxation, recreation, study, and meditation.” Each living deck would include six staterooms, which together would take up about half the deck’s floor space. Staterooms would each include a small viewport, a folding bunk, a desk, and storage cabinets.

When not in their staterooms, off-duty crewmembers could hang out in the multi-purpose wardroom, which would include portable dining tables with zero-gravity restraints in place of conventional seats. Dorrenbacher explained that the wardroom could be “quickly and easily” converted into a gym, theater, meeting room, or recreation room.

Cabinets in the galley, adjacent to the wardroom, would be kept stocked with enough food for 90 days. Crewmembers could choose to serve themselves or could take it in turns to prepare meal trays for their crewmates. Dorrenbacher told his audience that meals would be “selected for maximum palatability with various degrees of wet and even fresh foods,” but provided few details about how the food would be handled in zero gravity.

The three living decks would each include a hygiene facility. Apparently configured for men only, these would each include a toilet, two urinals, two handwashing units, a shower, a clothes-washing machine, and a clothes dryer. Hygiene facilities would be located next to the water-recycling life-support machinery on each living deck.

MDAC proposed a novel approach to Station orbit maintenance. Some processed waste water would be electrolyzed (split into oxygen and hydrogen using electricity) and the hydrogen used to fuel low-thrust orbit-reboost resistojets on the Station’s hull. MDAC calculated that water delivered to the Station in food would be sufficient to maintain its orbital altitude.

MDAC placed the core module control consoles on the living decks adjacent to the wardrooms. The artificial-gravity module would include an identical control console on Deck 5. The primary control console – the Station’s “bridge” – would be located on Deck 3. The control consoles on Decks 1 and 5 would be considered secondary. They would serve as backups for the Deck 3 primary console, and would also support experiments: they might, for example, be used to monitor data arriving from the FFMs.

Dorrenbacher then described an arbitrarily selected moment in the MDAC Station’s 10-year career to illustrate possible activities of on-duty and off-duty crewmembers. At 2030 hours Greenwich Mean Time on 26 March 1985, the flight-crew commander would be at work conducting safety checks on space suits stored on level 3 of the core module central tunnel. The shift’s other on-duty flight-crew member would, meanwhile, sample the Deck 1 water system to ensure that it contained no harmful bacteria.

Two of the scientist/engineers would be at work in the Deck 2 labs and two elsewhere. The physician would analyze crew blood and urine samples in the biomedical lab, while the psychologist would analyze data on “crew skill retention in extended zero gravity” in the man/system integration lab. The geologist/photo-optical engineer, meanwhile, would install and align sensors in the Earth Survey AM docked to Deck 2, and the astronomer/systems engineer would monitor data from the X-Ray Telescope FFM at the secondary control console on Deck 5.

The six off-duty crewmembers, having just finished their late meal, would all be found on Deck 3. The operations director, a flight-crew member, would take a shower in the hygiene facility, while the physician, a scientist/engineer, would watch a video-taped television program in his stateroom before going to sleep. The other off-duty crewmembers would be in the wardroom. The station controller, a flight-crew member, would compete against the astrophysicist, a scientist/engineer, in a simulated time-distance race on stationary exercise bikes. Nearby, the biologist and the electro-mechanical engineer, both scientist/engineers, would compete at “computer football.”

Conceptual 100-man Space Base design. Image: NASA.

Dorrenbacher concluded his presentation by assuring his audience that MDAC’s 12-man Space Station would be a “low-cost, flexible, international research facility” built using known technology (that is, mostly adaptations and upgrades of Skylab hardware). Furthermore, its modules would be readily adaptable to future NASA/ESRO missions: specifically, to serving as building blocks in the 100-man Space Base.

As noted earlier, NASA had instructed MDAC to design its 12-man Space Station to be launched on a Saturn V. Dorrenbacher failed to mention to his European hosts, however, that NASA Administrator Paine had announced on 13 January 1970, six months before the Paris briefing, that Saturn V production, already on standby, would be permanently ended, and that the last Saturn V, previously assigned to the Apollo 20 moon mission, would be reassigned to launch Skylab A. He also neglected to mention that NASA had directed NAR and MDAC in early May to begin considering designs for Space Stations that could be assembled solely from modules launched in the Shuttle Orbiter’s cargo bay.

On 30 June 1970, NASA issued Phase B extension contracts to MDAC and NAR. Less than two months after the Paris meeting (29 July 1970), NASA directed MDAC and NAR to study only Shuttle-launched modular stations. A week later, Paine announced that he would step down as NASA Administrator. Following his departure on 15 September 1970, NASA moved rapidly to toe the line on the Nixon Administration’s emerging space policy. That policy gave lukewarm support to the Space Shuttle and left the Space Station it was meant to serve in limbo.

On 5 January 1972, NASA Administrator James Fletcher announced that President Nixon’s FY 1973 NASA budget request included modest funds to begin development of a partially reusable Space Shuttle. Though little mention was made of a Space Station, Phase B studies lingered on until late in the year. On 29 November 1972, Fletcher formally abolished NASA’s Space Station Task Force and established the Sortie Lab Task Force. The Sortie Lab was intended to ride in the Shuttle Orbiter’s cargo bay, providing an interim Space Station-type research capability during Shuttle missions (“sorties”) lasting up to 30 days. In August 1973, NASA and ESRO agreed that the latter should develop the Sortie Lab, which became known subsequently as Spacelab.

Development and Use of a 12-Man Space Station, MDC G0583, C. Dorrenbacher, McDonnell Douglas Astronautics Company; Briefing to the European Space Research Organization on Space Station Plans and Programs in Paris, France, 3-5 June 1970.

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